It is now well known that heating devices which generate infrared radiation can be effective and efficient in certain applications; for example, a single jet burner can be connected to emit a high temperature effluent into a length of metal tubing which, because of the passage of the effluent therethrough, is heated to a temperature where it emits infrared radiation. The typical installation utilizes a burner which produces a relatively long high pressure flame front.
A second example of prior art infrared heating devices comprises a burner tile, usually ceramic, which exhibits a large number of small diameter channels or performations extending through the tile from one face thereof to the opposte face. A mixture of air and gas is supplied to a plenum on one face of the tile and is ignitied so as to burn substantially at the opposite face of the tile whereby the tile becomes heated and emits infrared radiation. This device is most often operated in the open atmosphere such that the pressure at the ignition-combustion surface of the tile and the air entry is essentially atmospheric. Stated another way, the combustion area for this device is essentially unconfined.
It has now become desirable to utilize the perforated tile ceramic burner in other than atmospheric conditions for a number of important reasons and cooking applications may be cited as a good example of such use. First, the combustion chamber can be isolated from the heat utilization chamber or chambers so that the effluent or flue gases of the combustion process do not contaminate the food or other materials being processed in the heat utilization chamber or chambers. Secondly, secondary atmospheric air or variations in the pressure thereof do not interfere with the strict ratios of air to gas that are required for efficient combustion and thus for high energy recovery from the consumed fuel.